1. Eco Station Promotion Association, Eco Station no Fukyu ni Mukete, 1998 (in Japanese).
2. The Planning Center, EV Charge Strategic Plan, 1998.
3. http://www.epri.com//.
4. Toshi Koutsu Mondai Chosakai, Chushajyo Kensetsu no Tebiki 99, 1999 (in Japanese).
5. Chushajyo Seibi Suishin Kiko, Chushajyo Census, 1999 (in Japanese).